Catalysis of phosphosulfurization reactions



nited States CATALYSIS F PHOSPHOSULFURIZATION REACTIONS John A. Brown, Metuchen, N. J., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application April 25, 1957 Serial No. 654,990

Claims. (Cl. 260-139) This invention is concerned with the phosphosulfurizev tion of hydrocarbons to obtain additives that impart detergency, extreme pressure, and other properties to lubricants. This invention is more particularly concerned with an improved process for the phosphosulfurization of hydrocarbons, catalyzed by almost trace amounts of alkaline earth metal salts of sulfurized phenols, whereby the phosphosulfurization is greatly accelerated but the character of the final product is not undesirably influenced.

In brief compass, this invention proposes an improvement of the process wherein a phosphorus sulfide is reacted with a hydrocarbon material havinga molecular weight in the range of 500 to 100,000, at a temperature in the range of 350 to 600 F., to obtain a product useful as a lubricant additive and containing at least 2 wt. percent preferably 3 to 4 wt. percent of combined phosphorus and at least 4 wt. percent, preferably 5 to 6 Wt. percent of combined sulfur. The improvement of this invention comprises catalyzing the reaction between the phosphosulfide and hydrocarbon with a catalytic amount in the range of 0.0001 to 0.9 wt. percent and preferably about 0.001 to 0.1 wt. percent of an oil soluble alkaline earth metal salt of a sulfurized phenol whereby the reaction rate is substantially increased.

'It is known to phosphosulfurize hydrocarbons and pe troleum fractions to obtain additive materials useful in lubricants to improve their properties. This invention is based on the discovery that the reaction time of a phosatent final product.

metal salt of a sulfurized alkyl phenol, i. e., a phenol sulphosulfurization reaction can be materially decreased by as much as or more, through the agency of almost trace amounts of phenol sulfide metal salts that serve to effectively catalyze the reaction. It is an important concept of this invention to use only trace or minute amounts of the catalyst in the range of 0.001 to 0.1 wt. percent, based on the combined reaction mixture. Larger amounts of the catalyst, while being no more effective, would appear in and might undesirably influence the character of the final product. By the process of this invention, most phosphosulfurization reactions can be carried out in 2 to 7 hours, which is a considerably lesser period of time than is obtained with those processes known to the prior art.

While broadly any hydrocarbon material, e. g., .parafiin waxes, can be subjected to phosphosulfurization in the manner of this invention, there are two primary, substantially aliphatic hydrocarbon, feed stocks that are of in terest: C to C monoolefin polymers having a molecular weight in the range of 500 to 100,000 and petroleum bright stocks boiling above 700 F. obtained by the distillation and deasphalting of crudes.

The monoolefin polymers useful in this invention are exemplified by polyethylene, polypropylene and poylisobutylene. It is intended to include, besides homopolymers, copolymers of monoolefins with other olefins such.

as isoprene, and with other materials such as styrene and similar vinyl compounds. The preferred polymers used have a molecular weight in the range of 500 to 2,500, and

, acted with a phosphosulfurized hydrocarbon, and prefer. 1

ice

are freely soluble in heptane at F. Polyisobutylene is particularly preferred.

The petroleum bright stocks useful in this invention are obtained by topping crude oils and extracting or deasphalting the residues to obtain materials having viscosities above SUS at 210 F., viscosity indices above 80, and initial boiling points above 700 F. Suitable crude oils are Pennsylvania and. Mid-Continent. Bright stocks can also be obtained from catalytic cracking cycle stocks. Suh bright stocks useful for phosphosulfurization are recognized products of petroleum refining and need no further definition.

Any sulfide of phosphorus can be used in this invention or even the elements themselves, in combination, can be used. Phosphorus pentasulfide, P 8 is preferred. 5 to 30 wt. percent, preferably 13 to 19 wt. percent of a phosphosulfide, based on combined reactants, is used.

This is sufficient to incorporate 2 to 6 wt. percent, preferably 3 to 4 wt. percent, of phosphorus and 4 to 12 wt.

percent, preferably 5 to 6 wt. percent, of sulfur in the The catalyst is an oil soluble alkaline earth These phenol sulfides are known to the art and can be 1 made in several ways. For example, an alkyl substituted phenol can be reacted with S 01 or elemental sult fur, preferably in the presence of a solvent, to obtain a mono-, dior polysulfide, as desired. The sulfide so obtained can then be reacted with an alkaline earth oxide or hydroxide to form a salt. compounds is more fully described in U. S. 2,362,291; U. S. 2,362,292; and other patents.

In a preferred embodiment of this invention, the phenol sulfide metal salt is further reacted with a phosphosulfide, preferably P 8 before being used as a catalyst. 5 to 15 wt. percent, preferably 8 to 10 wt. percent, based on the phenol sulfide metal salt, of the phosphosulfide is used and the reaction temperature is in the range of 250 to 300 F., for a time in therange of 3 to 4 hours. Such a phosphosulfide treated sulfurized phenol metal salt is more fully described in U. S. 2,451,345.

The phenolsulfide metal salt can also be further reably in this form of the invention it is reacted with the principal phosphosulfurized hydrocarbon product produced by the process of this invention. In this manner the catalyst can be obtained simply by recycling a small amount of the final reaction product.

In this embodiment, it is preferred to react the phosphosulfurized product with what are known as high alkalinity phenol sulfides. These sulfides may be admixed with high alkalinity sulfonates. These high alkalinity ma terials are obtained by using an excess of the hydroxide during their preparation, as is known by the art.

Whether used per se or as a reaction product with a phosphosulfide, or with a phosphosulfurized hydrocarbon, the phenol sulfide metal salt per se ispresent in the reaction zone in an amount in the range of 0.001 to 0.1 wt. percent, preferably 0.002 to 0.01 wt. percent, based on total reaction mass, which is sufiicient to elfectively catalyze the reaction; but insufficient to undesirably infiuence the character of the final product. Expressed ditferently, the metal introduced into the reaction zone,

by reason of the phenol sulfide metal salt is in the range of 0.0001 to 0.1wt. percent, based on total reaction mass.

., metal Any suitable reaction zone can be used.e; or glass-laboratory or plantreaction vessels can be used. The reaction temperature is in the range of 350 to 600 F., preferably 425-500 F. Pressure is not too Patented Feb. 24, 1959 v The preparation of these 7 asrenes.

a? material to ,thereaction, but is sufficient to prevent vapor; ization of the reactants and ,will normally be under 2 atmospheres. It is preferred to maintain a non-oxidizing atmosphere in the reaction zone and, therefore, the re action can be carried out under a blanket of nitrogen, carbon monoxide, refinery inert gas, fuel gas, etc. Generally theinert gas is used as a stripping gas during the reaction and the reaction mass is agitated. The reaction is usuallycompleted in under 7 hours. The reaction is considered complete when a cooled sample at room temperature will remain bright for at least 2 hours.

The reaction product is useful as an additive without any further treatment but, if desired, it can be further treated as previously indicated, or can be stripped, diluted, extracted, etc. This reaction pro-duct is also useful as. an intermediate topreparemore. complex lubricant additives as isknown in the art.

Example! 585 grams,of'lpolybutenewere reacted on a laboratory scale with 88 grams of P 8 in the presence of 5 grams of with wt. percent of P 5 at 300 F. for 3 hours in the presence of about 60% of diluent oil.

The polymer and P 8 were reacted at 425 F. under a nitrogen atmosphere, in a 3-neck, glass laboratory flask fitted with a glass stirrer, heating mantle, thermometer and thermo-regulator, and N bubbler. The reaction time was-4 hours when the catalyst was used. The reaction was considered to be complete when a sample cooled to room temperature remained bright for at least 2 hours. Under the same reaction conditions, in the same container, but in the absence of the catalyst, the reaction time to completion was 8 hours.

The P 8 treated polybutene had a phosphorus content of 3.40 wt. percent and a sulfur content of 6.04 wt. percent. This P 8 treated polybutene made with a catalyst according to this invention was indistinguishable from the uncatalyzed product.

Example II Thei polybutenezused in this-example was obtained in thesamemanner as in Example I, i. e., by the Friedel- Craftspolymerization of isobutylene (commercial prod uct: IndopolrH-300). It had a molecular weight of 1100 (Staudinger); 3,670 lbs. of this-polybutene werereacted=With- 552.lbs.= of "P 85 in a 2000 gal. glass-lined Pfaudler kettle with associated heating and feed lines. The reaction was carried out at a temperature of 425 F. under a nitrogen atmosphere with agitation. When carried out in the presence of a trace amount (less than 0.01 wt. percent) of a catalyst prepared by reacting P 8 treated wt. percent) polybutene with high alkalinity barium nonyl phenol sulfide and high alkalinity barium sulfonate in about equal proportions, the reaction time to completion was eight hours. The same material, when, reacted under the same conditions but in the absence of the-catalyst, took 14 hours to complete.

Example III The,-polybutene describedin Example 1 wasreacted with- 15 wt; percent of P 8 under the same conditions a temperaturepof about 300-350 F., 32 wt. percent of The catalyst was obtained by reacting at:

i h. lka ni y arium, alt, f a. ncuylrhenql ulfide.

and 32 wt. percent of a high alkalinity barium sulfonate, with the reaction product obtained by reacting 15 wt. percent of P 5 with a polybutene having a molecular weight of 1100. The nonyl phenol sulfide barium salt was in admixture with an equal wt. percent of a high alkalinity barium sulfonatehaving a; molecular; weight of about 1000, obtained. by reacting barium hydroxide with a sulfonate obtained by sulfuric acid treatment of a synthetic alkyl benzene. In the; presence of neu-- tralized phosphosulfurized polybutenecatalyst, the: reaction was completed in two hours in the laboratory, whereas in the absence of; thecatalyst thereaction time required was 8 hours.

xamnla r In a plant scale process of reacting at 430-440 F. 15 wt. percent of P 5 with thepolybutene of Example I, 0.02 wt. percent of high alkalinity barium nonyl phenol sulfide has been regularly used with reaction times of 4'- to 8 hours, as compared to reaction times of 14 hours uncatalyzed.

Having described this invention, what is sought to be protected by Letters Patent is succinctly set forth in the following claims.

What is claimed is:

1. In a process wherein a phosphosulfide is. reacted with a hydrocarbon material having a molecular weight in the range of 500-100,000at a temperature in the range of 350 to 600 F., to obtain a product useful as a lubri: cant additive containing above. 2 wt. percent of combined phosphorus and above 4 wt. percent of combined sulfur; the improvement which comprises catalyzing the reaction between said phosphosulfide and hydrocarbon material by the use of 0.0001 to 0.9 wt. percent of an oil soluble alkaline earth metal salt of a phenol sulfide whereby the reaction rate is substantially increased, wherein said alkaline earth metal salt is selected from the group consisting of calcium and barium, and wherein said phenol sulfide is an alkyl phenol sulfide having 6-12 carbon atoms in the alkyl chain.

2. The process of claim 1 wherein saidalkaline earth metal salt, before being used as a catalyst, is reacted with a material selected from the group consisting of phosphosulfurized hydrocarbons and'phosphosulfides.

3. In a process wherein a monoolefip polymer having a molecular weight in the range of 500 to 2500 is reacted at'a temperatureinth'e range of'350" to 600 F. to obtain a product useful as a lubricantadditive and'conta'iningin the'range of 3 to 4 wt. percent of'combinedph'osphorus' and in the range of 5 to 6 wt. percent of com-.

bined' sulfur, the improvement which comprises catalyzingthe reaction through the use of 0.002to 0.01"wt'. percent of an oil'soluble barium salt of an alkylphenol sulfide tion'with about 0.01 wt. percent of anoii soluble catalyst.

prepared by reacting. in about equal proportions P 5 treated polyisobutylene, high alkalinity barium nonyl phenol sulfide, and high alkalinity barium. sulfonate.

5. The process of claim 1 wherein said hydrocarbon material .is a substantially aliphatic hydrocarbon material having a molecular weight in the range of 500-100,000.

References Cited in'the file of this patent UNITED STATES PATENTS 2,379,313 May June 26, 1945 

1. IN A PROCESS WHEREIN A PHOSPHOSULFIDE IS REACTED WITH A HYDROCARBON MATERIAL HAVING A MOLECULAR WEIGHT IN THE RANGE OF 500-100,000 AT A TEMPERATURE IN THE RANGE OF 350* TO 600*F., TO OBTAIN A PRODUCT USEFUL AS A LUBRICANT ADDITIVE CONTAINING ABOVE 2 WT PERCENT OF COMBINED PHOSPHORUS AND ABOVE 4 WT PERCENT OF COMBINED SULFUR; THE IMPROVEMENT WHICH COMPRISES CATALYZING THE REACTION BETWEEN SAID PHOSPHOSULFIDE AND HYDROCARBON MATERIAL BY THE USE OF 0.0001 TO 0.9 WT. PERCENT OF AN OIL SOLUBLE ALKALINE EARTH METAL SALT OF A PHENOL SULFIDE WHEREBY THE REACTION RATE IS SUBSTANTIALLY INCREASED, WHEREIN SAID ALKALINE EARTH METAL SALT IS SELECTED FROM THE GROUP CONSISTING OF CALCIUM AND BRARIUM, AND WHEREIN SAID PHENOL SULFIDE IS AN ALKYL PHENOL SULFIDE HAVING 6-12 CARBON ATOMS IN THE ALKYL CHAIN. 